Alarm systems, such as fire alarm systems, typically include a plurality of notification appliances (e.g. horn/strobe units) installed throughout a monitored building that are configured to be activated upon the detection of an alarm condition, such as the presence of fire or smoke. Occupants of the building may thereby be notified of a potentially hazardous condition and may evacuate the building or take other appropriate action. It is therefore important that the components of alarm systems always be in good working order. To that end, fire alarm codes and regulations require that fire alarm systems be provided with a secondary power source, such as a rechargeable battery or a set of rechargeable batteries (commonly referred to as a “battery backup”) capable of providing power for a predetermined amount of time if an alarm system's primary power source experiences an outage.
The capacity of a battery backup may decline as a battery ages. Such degradation of capacity may result from environmental conditions, over-discharge, and/or mishandling of a battery, for example. It is therefore necessary to periodically test the capacities of battery backups in alarm systems to ensure that a sufficient amount of backup power can be provided to system components when necessary. Most jurisdictions require that battery backups be tested annually, and that during such testing it be demonstrated that a battery backup has adequate capacity to provide respective alarm system components (e.g., alarm panels, notification devices, etc.) with sufficient electrical power to sustain a standby period of 24 hours followed by an alarm period of at least 5 minutes.
Several methods have been developed for testing the capacities of battery backups in alarm systems. One method, which may be referred to as a “live test,” involves switching an alarm system from a primary AC power source to a battery backup power source for a standby period of predetermined length (e.g., 24 hours), followed immediately by placing the notification appliances in the alarm system in an alarm mode for an alarm period of predetermined length (e.g., 5 minutes). The notification appliances are physically observed during the alarm period and the voltage output of each battery backup is measured at the end of the alarm period to verify sufficient capacity. One shortcoming of this live test method is that it requires personnel to simultaneously monitor all of the notification appliances in an alarm system and to simultaneously measure the output of all of the batteries in an alarm system during and after the alarm period. This can be very burdensome and expensive since many personnel are required to test systems that have large numbers of notification appliances installed in locations that are remote from one another.
Another test method, which may be referred to as an “offline test,” involves removing battery backups from an alarm system and discharging them in on a bench, such as at an offsite test facility, in order to determine the capacities of the battery backups. As will be appreciated, a shortcoming of this method is that an alarm system must be operated without battery backups during the testing period which poses a safety hazard. Moreover, offline discharging may only provide an approximation of a battery backup's true operational (i.e. online) capacity.